In presently available printing machines, such as the product line R 700 commercially sold by MAN Roland Druckmaschinen AG, a vertically movable guard is provided which covers approximately one-half the height of the printing unit on the delivery side of a printing unit. Above the vertically movable guard, further protection is provided in front of the inking-unit rollers and the ink fountain when in their normal operating positions. The vertically movable guard is supported by linear guides attached to side pillars of the machine frame on the drive and service sides and is actuated via a pneumatic working cylinder.
DE 42 24 832 A1 discloses a device which is vertically movable as a guard in front of the printing-unit cylinders of the printing machine and which is designed as a magazine for the automatic changing of printing plates. This magazine is pivotable about a horizontal shaft, with the shaft being guided at each of its opposite ends in a linear guide attached to the side pillars at the drive side and service side of the machine. As can be seen particularly from FIG. 2 of this publication, the entire height of this magazine covers the printing unit. Therefore care must be taken to avoid that an ink fountain located in the upper end part of the printing unit is moveable between its aperture and thrown-off positions without coming into the path of movement of the magazine.
An ink fountain mounted so as to be capable of being thrown on and thrown off relative to an ink-fountain roller is known from DE 40 12 949 C1. This throw-on and throw-off mounting of an ink fountain relative to an ink-fountain roller serves, as is known, for the cleaning and maintenance of the ink fountain or the metering elements cooperating with the ink-fountain roller.